1. Field of the Invention
This invention relates to camera periscopes and more particularly to a novel periscope construction providing substantially full viewing of the visual image by the viewer with suppression of stray light normally scattered into the lens of the camera.
2. Brief Description of the Prior Art
In the past, it has been a conventional practice to mount a movie camera onto a gunsight carried on an aircraft so that a film record may be taken of the pilot's aiming and firing procedures with respect to the gunsight and the target. To achieve this purpose, the camera is usually mounted below the gunsight and a small periscope attached to the camera lens projects upwardly between the viewers eye and the gunsight target information displayed on the combining glass having the range or other pertinent lines scribed or otherwise projected thereon. However, the camera periscope frequently constitutes a major obstruction between the pilot's eye and the gunsight target information so that the viewer must make constant adjustments for the obstruction by moving his head or body so as to clearly see the target information on the combining glass.
In an effort to reduce the obstruction of the periscope, attempts have been made to construct periscopes entirely of glass or other transparent materials. Difficulties have been encountered in these attempts which are due primarily to the fact that stray light is scattered into the camera lens which causes loss of image contrast and resolution. Therefore, the viewer must accept the disadvantages of a large obstruction in his line of sight or the viewer must accept the disadvantages of contrast and resolution loss caused by scattering of stray light.
Therefore, a long standing need has existed to provide a novel camera periscope which will not substantially obstruct the viewing of gunsight target information by the viewer and yet which will reduce the effects of scattered stray light.